Machine for grinding



13, 4 R. w. OSBORN 2,211,350

MACHINE FOR GRINDING Filec} April 7, 1939 3 Sheets-Sheet l FIG.

Attorney Aug. 13, I940. R. W. OSBORN v 2,211,350

MACHINE FOR GRINDING Filed April '7, 1939 3 Sheets-Sheet 2 (74 FIG. 5. V 7 70 F &

F |G.7. FI 8 ll 5a 50 INVENTOR RALPH w. OSBORN.

Attorney 3 Sheets-Sheet 3 RALPH W. OSBORN.

R. w. osBoRN MACHINE FOR GRINDING Filed April 7. 1939 Aug. 13, 1940.

Patented Aug. 13, 1940 2 1 STATES A'I'ENT QFFICE MAOHINE FOR GRINDING Ralph W. Osbern, Muskegon, Mich, assignor to Johnson Products, Inc, Muskegon Heights, Mich, a corporation Application April 7, 1939, Serial No. 266,602

9 Claims. (01. 51100) My invention relates to a method of grinding In the drawingand a machine for accomplishing this method and Fig. 1 is aside view of my invention, parts being more particularly to a method wherein a variety broken away in order to expedite the showing.

of shapes may be ground on the ends of valve Fig. 2 is a plan View of the machine shown in "6 tappets of various shapes and sizes. Fig. 1, parts likewise being broken away to expe- One of the problems encoutered in present day dite and clarify matters. grinding and finishing is the uneven wearing Fig. 3 is a fragmentary sectional view taken away of the abrasive wheel with the attendant along the plane of the line 33 of Fig. 1. necessity of then suspending operation in order to Fig. 4 is a fragmentary sectional view taken true the wheel to its initial shape. This probalong the line 44 of Fig. 2. 10 lem is a serious one for several reasons. First, Fig. 5 is a diagrammatic View, in plan, illusthe gradual wearing away of the most used part trating the path of movement of an article relaof the wheel results in the gradual production of tive to a finishing or roughing wheel.

work which may be below standard. Second, Fig. 6 is a full size diagrammatic plan view dis valuable production time is lost during the operclosing the various steps in the grinding oper- 5 ation of trueing the wheel. ation when grinding a fiat surface or a conical My invention overcomes the above problem surface on the end of a tappet or similar piece.

inasmuch as there is an even and gradual grind- Figs. '7, 8 and 9 are side views of three different ing entirely across the wheel and of course the shapes which may be produced in accordance with .20 revolving of the wheel wears it away circumferthis invention. entially at an even rate. Thus the wheel does not Fig. 10 is a full size diagrammatic plan view wear down at any one spot or place but wears illustrating the steps in the production of a tap evenly and consequently a minimum dressing pet or the like having a spherical end and the thereof is required. As a matter of fact, the shape of the cam needed to produce the same.

.5 movement of the points of grinding contact across Fig. 11 is a sectional view taken along the plane the wheel are in a straight line and thus any high of the line ll--H of Fig. 10. points which might form or tend to form are cut Fig. 12 is a sectional view taken along the plane away by the actual grinding of the work itself of the line [2-42 of Fig. 11. upon succeeding operations. As shown in Figs. 1 and 2, numeral 5 indicates a .30 Another very material adyantage is that the base or frame having a raised portion 6 progrinding occurs at only a point and thus the coolvided with ways or grooves 1, one groove being ing thereof is facilitated. This is true even shown in Fig. 3. though a fiat surface is being ground or finished. A subbase 8 has ribs 9 entering the ways 1 If a flat surface were produced by a fiat contact whereby the subbase can slide or reciprocate obviously the central portions are more or less during the action of the machine as herein de- 35 inaccessible either by air or cooling fluids and the scribed.

heating problem comes to the fore. In my novel The subbase 8 is grooved at H] to receive rib-s method this problem is automatically solved. H which extend downwardly from the upper Another important advantage is that the mabase l2.

.40 chine may be used to grind a variety of shapes This upper base or unit l2 has a fixed member 40 merely by changing cams. This feature makes 83, see Fig. 2, which rotatably receives the headed it possible for one machine to take the place of end of an adjusting screw 14 threadedly passing several machines that will grind only one or two through an extension or lug l5 formed as one shapes. with the subbase 8.

5 For the purpose of illustrating my invention 1 The unit l2 has a shaft [6 which carries a have shown in the accompanying drawings one grinding wheel ll. The shaft and grinding wheel form thereof, this form giving satisfactory'and may be motor driven. reliable results in practice, although it is to be From the above construction it will be underunderstood that the various instrumentalities of stood that normally the upper unit [2 is rigid which my invention consists, and by use of which with the subbase 8 which carries the same but 5 the desired method practiced, can be variously arthat adjustment may be made therebetween by ranged and organized and that my invention is rotation of the threaded screw M in the desired not limited to the precise arrangement and ordirection in order to properly position the periphganization of the instrumentalities as herein cry of the grinding wheel relative to the work shown and described. which is being ground. For instance, adjust- 55 ment of these members may be made when the chosen cam from the group of cams is initially inserted and also adjustment may be made to compensate for grinding wheel wear.

As shown in Figs. 1 and 2, a boss l8 extends rearwardly from the sliding base 8. A wall is extends upwardly from the base 5 and receives a spring plunger assembly now to be described. This spring means causes engagement between the cam and its follower as will be readily understood as the description proceeds.

The wall l9 has a threaded opening 20 therein. A hollow sleeve 2|, exteriorly threaded, is screwed to a desired position within the opening and a lock nut 22 looks it into position. A coiled spring 23 is inserted within the hollow sleeve and a slidable plunger placed thereagainst. The outer end of the plunger, numbered 2 is urged against the abutment l8 and thus the entire assembly of the sliding base l5, grinding wheel 11, and its prime mover are slid outwardly under controlled operation as will be described later. There may be one or more of the spring plunger assemblies.

An arm 26 extends upwardly from the sliding base 8 and carries a seating recess formed by a rear wall 27 and end walls 28. Holes extend downwardly through the bottom of the recess and studs 30, one of these being shown in Fig. 1, thread upwardly into the cam strip SI and firmly hold it in position.

The cam strips 3| are interchangeable as clesired and may be backed by shims of tapered or flat construction of various thicknesses as desired.

The base 5 is extended as shown and has a supporting and housing structure 35 shaped as shown to revolubly receive the trunnion 31 of the turntable 38. A track 40 is machined on the underside of the turntable and faces downwardly. A second track 39 is formed upon the supporting structure 35 in opposed relationship to the track 40 and thus the table may be rotated in free and easy fashion.

The trunnion 31 of the turntable is provided with a worm gear 4! driven by the worm 42 which in turn is driven by the motor 44 through suitable reduction gearing 43. Thus the turntable is caused to revolve slowly at the chosen speed, which speed may vary widely from even 1 to 12 R. P. M.

As shown in Figs. 1 and 2, work holders 45 are spaced upon the turntable 38 concentrically and motors 4B drive the chucks 41 therein by the belts 83. Thus the articles or tappets 5!], see Fig. 2, are rotated about their longitudinal axes as they are bodily moved or translated around the turntable circle. Bolts 5| hold the several units in place.

Directly below each unit, see Fig. 4, is a roller 52. A headed stud 53 extends centrally through this roller to serve as its axis and enters the lower side of the turntable at 54. A spacer 55 maintains the roller in proper position for contact with the chosen cam.

The start of this contact is indicated in Fig. 2. It will be apparent that rotation of the turntable 38 in the direction indicated by the arrow A causes movement of the sliding base 8 and the upper sliding base l2, which bases are kept integral, to the left against the action of the spring plunger 24. However, the work holder 45 and the work which it carries are also advancing to the left. The shape of the cam and its follower is so made as to have a slight or virtual engagement during the entire travel of the rotatingwork across the periphery of the grinding wheel. As shown in Fig. 2, the cam 3! has a raise 56 which becomes effective at the time when the center of the work alines with the terminal side of the wheel to elevate or withdraw the work from contact with the wheel.

As shown in Fig. 5, numeral 7!] is a grinding wheel which may be a finishing wheel of three inches width, more or less. The center of the turntable is at "H, the roller is '52 and the tappet is 59. An intermediate roller position is shown in dotted lines.

The advancement of the roller 12 towards the periphery of the grinding wheel is indicated by the numeral '13. Similarly, the advancement of the work is designated by 74. As these distances are different it will be apparent that a cam surface is needed to cause proper movement of the related parts. Also, a cam is needed to withdraw the work from the wheel at the finish of the grind to prevent the trailing half of the work from contacting the wheel after the cut or grind has been completed.

Referring now to Fig. 6, 58 indicates the work, which may be a valve tappet, shown in five consecutive positions, namely, I, II, III, IV and V, these positions following one another in time sequence. And, actually, the cam, which is now to be described, causes the valve tappet, which is being ground, to pass through an infinite number of positions whereby the planes along which grinding occurs really become points and the loci of all these points is the resulting cutting curve or finished surface.

The work 50, when in I position, extends beyond the corner of the grinding Wheel a slight distance as indicated by 75. This is the extra metal which is to be removed when making a flat cut-01f as shown in Fig. 7. The point 16 is the point which first contacts the wheel.

The term WR designates the radius from this point 15 to the center of the turntable. The line RI extends from the center of the first or I position of the tappet to the center of the turntable and the cam roller 52 is located on this line. The cam roller when at this point is designated 52I and the center of the roller is ID. A tangent line is drawn next to the roller, this line representing the cam which is to be so positioned relatively to the roller. TI is this line. For convenience in illustration the point PI is located to the left of TI and is the same point. That is, this point maintains the tappet with its point l6 as shown.

The curved line which passes through I9 is a part of a circumference drawn with the center of the turntable as its center. It is marked RR.

As shown at the left of Fig. 6, the tappet or work moves upwardly to the II position. The line 8!] indicates the edge of the grinding wheel and the tappet is cut as indicated by this line 8!] and the line 8| inasmuch as the tappet revolves about its longitudinal axis. In other words, an annulus having a cross section as shown at 82 is removed.

The radius RII corresponds to the second or II position just referred to and this radius crosses the roller radius at 110. The roller 5288 has the tangent TII thereagainst. The distance between this tangent and the tangent TI is represented by the numeral 11. So the rollers point of operation moves towards the grinding wheel this amount.

Referring to the left part of Fig. 6, numeral 83 indicates the initial position of the periphery of 'the grinding'wheel. Line 813 indicates the second position to be attained. The distance to be moved is indicated between these two lines'Bil and 83 and is distance I8.

Thus I8 minus ii is the difference which gives the point PII. In other words, the cam must slightly increase the movement of the roller 52 in order that the grinding wheel I? may be sufficiently retracted and grinding may not be unduly increased.

The tappet is next moved to position III. The periphery of the wheel must now be located at 84. The corresponding axis or radius RIII locates the roller center at 1118 and the roller is shown at 52111 and the tangent at T111. Numerai indicates the shifting of the roller to the left from its initial position. However, the necessary movement is that of 33, namely the distance between 88 and M. Measuring this distance from the cam base line one obtains the point PIII. Thus three points on the cam have been obtained.

The tappet is now moved to position IV and 8B shows the desired position of the grinding wheel, 89 being the distance the wheel must be moved from its initial position. RIV is the radius which crosses line M to give center IVE The roller 521V has the tangent TIV at its left and the distance is the lateral movement of the roller. The difference between distances 55 and 9&3 gives the distance of the desired point PIV from the cam base line 81.

The tappet now is moved upwardly to position V. The corresponding radius is RV and the point V9 is obtained as the center of the roller. 52V is the roller. TV is the tangent. The lateral shifting of the roller is indicated by the numeral 92. Numeral BI is the cutting plane and the distance thereto from its initial position is indicated by 93. The difference between the distances 92 and I33 gives the cam height or the point PV. Thus the main part of the cam is obtained. The final portion of the cam is now slanted upwardly so as to quickly separate the tappet and the grinding wheel but it must not be steep enough to interfere with the roller 52V, this being the roller in its final position.

The above operations will give a piece of work having its end flat, as shown in Fig. '7. However, it will be apparent that the cam. might be so shaped as to make position IV the concluding one whereby the tappet is lifted from the wheel thereabouts, instead of at position V, and the finished piece of work will be shaped more or less as shown in Fig. 9.

Referring now to Fig. 10, wherein a tappet or piece as shown. in Figs. 8 and 12 is to be formed, we indicates the initial position of the tappet. The tappet extends slightly beyond the corner of the grinding wheel as shown. The initial contact point is at I0 I. Radius IElZ is from the cen ter of the turntable (not shown) and curve M33 is the concentric path of the roller 52.

Thus Hi l is the center of the roller, which roller is indicated by numeral H35 in this position. Point H16 may be assumed as the starting point of the cam.

The tappet is now assumed to be moved upwardly to II]? and the desired curvature at Hi8. although only a portion of this curvature has actually been ground at this point. A line, parallel to the initial periphery of the wheel H0, is drawn at me tangent to the curve and then a perpendicular III is erected. This gives the point of tangency and it is at this point that the grinding occurs at this particular instant. The distance H2 is the distance'that the grinding wheel must retreat during this phase of the swinging movement of the tappet.

The radius H3 crosses the curve I03 to position the roller I I4 with the center I I5. The center H5 has shifted from its first position I94 to the left a distance indicated by numeral H6.

The next position of the tappet is at I I? and by plotting in the same manner as described the distance H8 is determined as is also the distance H9.

In the next position I20 the distances I2I and 22 are determined.

When the tappet reaches the upper position wherein its axis, when prolonged, alines with the terminal side of the wheel, then I23 is the distance which must be taken care of by the movementof the cam and the roller. Distance IN is the distance taken care of or compensated for by the movement of the roller. The small distance it is the height of the crown of the tappet.

Numeral 35 is the cam having openings I29 and a base line I28. The point I06 is located upon the base line to start with. The difference between ii; and H6 gives the height of point I3I above the base line. Similarly, the difference between H8 and H9 locates the point I32.

The next point on the cam is located by the difference between IZI and I22 and is designated S33. Point I34 is located by the difference beween I23 and I24.

The cam is next curved upwardly at I35 but this curvature should be less than the curvature of the roller in order to prevent the roller from leaving the cam prior to the point I3 5. The cam has a terminal curve at I36 and a beginning curve at I31.

Fig. 11 indicates a sectional view which may be taken along the line II-II of Fig. 10-, showing that the work might be of many different shapes and sizes.

The operation of my invention will be apparent from the preceding description. The linear speed of the grinding wheel may be 450% feet per minute, more or less. The tappets or pieces may be revolved at 1800 R. P. M., more or less. Both may be rotated downwardly as shown by the arrows at ten in Fig. 10, or'in opposite directions.

The advantages of this machine are many, the wheel may be dressed straight across or in the shape of an irregular or regular curve, the cam being varied to adapt the path of the work to the shape of the wheel. The cam also causes the grinding of the work to keep the wheel dressed to the same general contour at all times.

By changing cams, a variety of shapes may be ground on the ends of various sizes of tappets and pieces. This makes the machine universally adapted for work that would otherwise have to be ground on several different special machines.

The design of the machine is such that by adding additional grinding wheel units at various locations around the turntable, the work may be- 1. A grinding or polishing machine of the class described. comprising, a stationary base having a track therein, a sliding base having means slidable on said track, a grinding wheel revolubly mounted upon said sliding base, a motor attached to the wheel for driving the same, said grinding wheel revolving about a horizontal axis, a turntable revolving about a vertical axis, revoluble chuck means mounted near the outer edge of said turntable, the prolongation of the chuck axis passing substantially through the axis of the grinding wheel and also, when the turntable is turned to one of its positions, passing along one side of the grinding wheel, spring means for urging the sliding base towards the turntable, and cam means for limiting the amount of said sliding movement, said cam means being of such' contour as to cause a slight engagement between the object which is held in said chuck and is being ground or finished for the purpose described and the grinding wheel.

2. A grinding machine as set forth in claim 1 in which the cam means is so shaped as to cause abrupt separation of the sliding base and the turntable when the turntable passes that point where the chuck axis is in alinement with the side of the grinding wheel.

3. A machine of the class described in claim 1 which constant speed motor driven means is provided for rotating the said chuck.

4. In combination, a base, a second base slidably mounted thereon, a horizontal shaft on the second base at right angles to the direction of sliding movement, a grinding wheel on said shaft, a horizontal turntable, means to drive the same, a work carrier on said turntable, said carrier, in one position, holding the work at right angles 'to the peripheral face of the wheel, cam means onthe second base, follower means on the turntable, spring means urging engagement between the cam and its follower, the shape of the cam and its follower being such as to substantially cause the same degree of engagement along the face of the wheel until the right angled position is reached, and then to cause a separation between vthe wheel and the article which is being finished or ground.

5. A combination as set forth in claim 4 in which the axis of the turntable lies on a prolongation of a plane passing along one side of the grinding wheel.

6. A combination of elements as set forth in claim 4 in which the axis of the turntable is vertical and in which the turntable has a plurality of work carriers mounted thereon and a cam follower comprising a roller located underneath each of the carriers.

'7. A combination of elements as set forth in claim 4 in which the cam and its follower causes separation of the wheel and the article prior to said right angled position.

8. A machine of the class described comprising a grinding wheel revolubly mounted on a movable base, means for revolving the wheel, said grinding wheel revolving about a horizontal axis, a turntable revolving about a vertical axis, revoluole chuck means mounted on said turntable, the prolongation of the axis of the chuck means passing through the axis of the grinding wheel and also, when the turntable is turned to one of its positions, passing along one side of the grinding wheel, means for moving the base, relative to the turntable, including a cam and follower, said cam means being of such contour as to cause a slight engagement between the object which is being held in said chuck and the grinding wheel.

9. In a construction of the class described, a turntable turning in a horizontal plane, a series of concentrically positioned chucks thereon, each chuck having its axis radially positioned with respect to the turntable, means for revolving each chuck about its individual axis, a common disc grinding wheel, means for revolving the same, a slidable base for the wheel and its revolving means, said base being so positioned that the terminal edge is substantially along a radius of the turntable and interengaging means between the said movable base and the turntable whereby the work in each chuck is initially engaged on the side of the grinding wheel and then mains tained in engagement completely thereacross for the purpose described.

RALPH W. OSBORN. 

